child care—until now considered outside the economic market and nonmone-tary in nature—have begun to receive closer attention.
Several workers have hypothesized that there are linkages between fertility levels and the productive (including entrepreneurial) capabilities of the labor force. Family size (or average number of children being cared for simultaneously over a considerable stretch of their pre-adult ages) has been proposed as being causally—and inversely-related to intelligence, child health and care, educational opportunities, and actual school performance. Such effects might be the outcome of two sets of causal factors: reduced "investment" in human resources when family income must be distributed over more children; and possible influences of larger family size as such, with income held constant. Most of the evidence available on the topic bears predominantly on the first class of effects, which, reduced to essentials, are really forms of intergenerational transmission of poverty, a long-familiar subject. Whether family size as such is significant for economic growth is still speculative at best and would probably require at least 10 to 20 years of intensive study to provide reasonably definitive answers, given the inherently longitudinal nature of the transmission processes in question.
However this may be, the processes may have much more significant, as well as visible, implications when the effects of family size are viewed directly in welfare terms, rather than as indirect productive inputs. The effects of rapid childbearing and shortened child spacing on infant nutrition and quality of child care, as well as on maternal health in low income countries, might turn out to be large. Such effects, along with many other "quality of life" indicators, are still largely "beyond GNP." However, even conservative allowance for their existence in benefit-cost terms could yield large income-equivalents. Indeed, given the substantial fraction of the total population annually involved directly with births in the high-fertility areas (perhaps one fifth or more, using a birth rate of 40 per 1,000 and assuming families of five or more including parents), the gains to individuals and families from fertility declines not only would tend to accrue more rapidly, but also might possibly be greater, than the corresponding macro-income effects that can be deduced using more conventional methods of measurement. Merely a one-child reduction in number of children ever born to each mother, if accompanied by commensurately extended intervals of child spacing, would affect the large majority of couples in the reproductive ages, and hence the majority of the total population, within as little as 5 to 10 years.
Socioeconomic Change and Fertility
Finally, a look at the reverse direction of interactions—from social and economic change to fertility—reveals an even scantier base of knowledge.ch more secondary position the role of diminishine returns: it would notelated collective consumption needs would stay largely unchanged for the better part of a decade, and